This is really my first time shooting anything. I read "How To Create Stunning Digital Photography" by Tony Northrup and about a quarter of "Picture Perfect Practice" by Roberto Valenzuela beforehand so I didn't go in completely blind.

The convention was sold out since it was a last minute thing for me, so I just walked around the entrance and park area. I didn't feel like explaining over and over again how to pose so I decided on practicing street style candids instead.

Here are a few of my shots with my Flickr at the bottom. They're all SOOC and unedited aside from the few that needed cropping. Let me know what you think and tell me what your favorites are! Thanks!

I agree that you should try to do posed shots. During my first cosplay event I just took photos of cosplayers who just happened to be posing.

When you ask cosplayers for a photo, they will pose for you and most of the time they would look at you even if there are other people joining in to take photos. Also, you can ask them to stand somewhere nearby where there are less background distractions.

If you're going to use lightroom and shoot raw, that will cover up a lot of exposure mistakes, but not focus, so nailing the focus is the most important thing to pay attention to.

I'm not a photographer, I just love looking at cosplay photography, and so take what I say with that in mind.
I think one of the strongest in the set is the first one you posted here, that Spider-Man one. For me, that one really works with the character of Spider-Man. I think with candid pictures, the most effective come when there's an understanding of the character by the person shooting. This is what makes that Spider-Man one work. To me it makes it real not just for the cosplayer, but for Peter Parker as well. I hope that makes sense. Sorry for intruding on the photography board, haha.